

import java.util.concurrent.TimeUnit;

public class Profiler {
    private static final ThreadLocal<Long> TIME_THREADLOCAL = new ThreadLocal<Long>() {
        @Override
        protected Long initialValue() {
            return System.currentTimeMillis();
        }
    };

    public static final void begin() {
            TIME_THREADLOCAL.set(System.currentTimeMillis());
        }
    public static final long end() {
            return System.currentTimeMillis() - TIME_THREADLOCAL.get();
        }
    public static void main(String[] args) throws Exception {
            Profiler.begin();
            TimeUnit.SECONDS.sleep(1);
            System.out.println("Cost: " + Profiler.end() + " mills");
        }
    }
